BigChef/README.md

# Big Chef

A Go-based tool for modifying XML, JSON, and text documents using XPath/JSONPath/Regex expressions and Lua transformations.

## Features

- **Multi-Format Processing**:
  - XML (XPath)
  - JSON (JSONPath) 
  - Text (Regex)
- **Node Value Modification**: Update text values in XML elements, JSON properties or text matches
- **Attribute Manipulation**: Modify XML attributes, JSON object keys or regex capture groups
- **Conditional Logic**: Apply transformations based on document content
- **Complex Operations**: 
  - Mathematical calculations
  - String manipulations
  - Date conversions
  - Structural changes
  - CSV/TSV parsing with comments and headers
  - Whole ass Lua environment
- **Error Handling**: Comprehensive error detection for:
  - Invalid XML/JSON
  - Malformed XPath/JSONPath
  - Lua syntax errors

## Usage Examples

### 1. Basic field modification
```xml
<!-- Input -->
<price>44.95</price>

<!-- Command -->
chef -xml "//price" "v=v*2" input.xml

<!-- Output -->
<price>89.9</price>
```

### 2. Supports glob patterns
```xml
chef -xml "//price" "v=v*2" data/**.xml
```

### 3. Attribute Update
```xml
<!-- Input -->
<item price="10.50"/>

<!-- Command -->
chef -xml "//item/@price" "v=v*2" input.xml

<!-- Output --> 
<item price="21"/>
```

### 3. JSONPath Transformation
```json
// Input
{
  "products": [
    {"name": "Widget", "price": 19.99},
    {"name": "Gadget", "price": 29.99}
  ]
}

// Command
chef -json "$.products[*].price" "v=v*0.75" input.json

// Output
{
  "products": [
    {"name": "Widget", "price": 14.99},
    {"name": "Gadget", "price": 22.49}
  ]
}
```

### 4. Regex Text Replacement
Regex works slightly differently, up to 12 match groups are provided as v1..v12 and s1..s12 for numbers and strings respectively.
A special shorthand "!num" is also provided that simply expands to `(\d*\.?\d+)`.
```xml
<!-- Input -->
<description>Price: $15.00 Special Offer</description>

<!-- Command -->
chef "Price: $!num Special Offer" "v1 = v1 * 0.92" input.xml

<!-- Output -->
<description>Price: $13.80 Special Offer</description>
```

### 5. Conditional Transformation
```xml
<!-- Input -->
<item stock="5" price="10.00"/>

<!-- Command -->
chef -xml "//item" "if tonumber(v.stock) > 0 then v.price = v.price * 0.8 end" input.xml

<!-- Output -->
<item stock="5" price="8.00"/>
```

### 6. CSV/TSV Processing
The Lua environment includes CSV parsing functions that support comments, headers, and custom delimiters.

```lua
-- Basic CSV parsing
local rows = fromCSV(csvText)

-- With options
local rows = fromCSV(csvText, {
    delimiter = "\t",        -- Tab delimiter for TSV (default: ",")
    hasHeaders = true,       -- First row is headers (default: false)
    hasComments = true       -- Filter lines starting with # (default: false)
})

-- Access by index
local value = rows[1][2]

-- Access by header name (when hasHeaders = true)
local value = rows[1].Name

-- Convert back to CSV
local csv = toCSV(rows, "\t")  -- Optional delimiter parameter
```

**Example with commented TSV file:**
```lua
-- Input file:
-- #mercenary_profiles
-- Id	Name	Value
-- 1	Test	100
-- 2	Test2	200

local csv = readFile("mercenaries.tsv")
local rows = fromCSV(csv, {
    delimiter = "\t",
    hasHeaders = true,
    hasComments = true
})

-- Access data
rows[1].Name  -- "Test"
rows[2].Value -- "200"
```

## Lua Helper Functions

The Lua environment includes many helper functions:

### Math Functions
- `min(a, b)`, `max(a, b)` - Min/max of two numbers
- `round(x, n)` - Round to n decimal places
- `floor(x)`, `ceil(x)` - Floor/ceiling functions

### String Functions
- `upper(s)`, `lower(s)` - Case conversion
- `trim(s)` - Remove leading/trailing whitespace
- `format(s, ...)` - String formatting
- `strsplit(inputstr, sep)` - Split string by separator

### CSV Functions
- `fromCSV(csv, options)` - Parse CSV/TSV text into table of rows
  - Options: `delimiter` (default: ","), `hasHeaders` (default: false), `hasComments` (default: false)
- `toCSV(rows, delimiter)` - Convert table of rows back to CSV text

### Conversion Functions
- `num(str)` - Convert string to number (returns 0 if invalid)
- `str(num)` - Convert number to string
- `is_number(str)` - Check if string is numeric

### Table Functions
- `isArray(t)` - Check if table is a sequential array
- `dump(table, depth)` - Print table structure recursively

### HTTP Functions
- `fetch(url, options)` - Make HTTP request, returns response table
  - Options: `method`, `headers`, `body`
  - Returns: `{status, statusText, ok, body, headers}`

### Regex Functions
- `re(pattern, input)` - Apply regex pattern, returns table with matches

## Installation

```bash
go build -o chef main.go
```

```bash
# Process XML file
./chef -xml "//price" "v=v*1.2" input.xml

# Process JSON file 
./chef -json "$.prices[*]" "v=v*0.9" input.json
```